JP4500648B2 - Immersion membrane separator - Google Patents

Description

  The present invention relates to a submerged membrane separator for purifying domestic wastewater, and more particularly to a submerged membrane separator suitable for a small septic tank.

  It is socially important to comprehensively purify domestic wastewater to prevent environmental pollution, and the application of the submerged membrane filtration method to small septic tanks is also focused on development (for example, , Japan Environmental Education Center, "Research Report on Practical Use of Small Domestic Wastewater Treatment System Introducing Membrane Treatment Method, 1992-1995"). For this method to be practical, it must not only be acceptable cost performance, but also be compact and easy to maintain. In particular, in terms of maintainability, it is necessary that the entire submerged membrane separation device installed in the septic tank can be easily taken out of the septic tank for inspection or the like and can be easily reattached to the septic tank.

  Conventionally, the membrane modules that have been studied are plate type and hollow fiber type, but it is not necessarily compact and economical as an immersion type membrane separation device for a small septic tank for up to about 10 people. Further, in the maintenance and management, there are problems that the entire apparatus is not originally configured to be detachable, that it is too heavy and that it is difficult to attach and detach, and that it is not easy to measure the dimensions when reattaching.

In order to solve this problem, a membrane module composed of a number of tubular membranes has been developed (for example, see Patent Documents 1 and 2). Although such a membrane module has significantly improved compactness and economic efficiency, such a membrane module is not always satisfactory in terms of maintenance.
JP 2002-166137 A JP 2002-166138 A

  The present invention has been made to solve the problems of the prior art. The entire apparatus can be easily attached and detached without using a special tool, can be reattached with high accuracy, and the filtration process can be easily resumed. An object of the present invention is to provide an immersion type membrane separation apparatus.

  The submerged membrane separation apparatus according to the present invention is attached to a membrane module that filters a liquid to be treated, a bubble supply device that supplies bubbles to the membrane module, and a side of the bubble supply device. An inner slide body extending upward, and a pipe-shaped outer slide body attached to the side of the membrane module and capable of sliding the inner slide body in the vertical direction. The outer slide body is a septic tank A guide body provided in advance is slidable in the vertical direction.

  According to the submerged membrane separation apparatus having the above configuration, the outer slide body and the inner slide body are respectively attached to the sides of the membrane module and the bubble supply device installed below the membrane module. The outer slide body attached to the membrane module is attached to a guide body previously installed in the septic tank so as to be slidable in the vertical direction. Furthermore, the inner slide body attached to the bubble supply device is attached to be slidable in the vertical direction inside the pipe-like interior of the outer slide body.

  Therefore, by installing the bubble supply device and the membrane module while sliding the inner slide body and the outer slide body respectively on the guide body of the septic tank, it is easy and accurate to immerse the membrane without the need for special tools. Equipment can be installed. In addition, even if the attachment and detachment is repeated for maintenance or the like, the attachment can be performed easily and accurately.

  Preferably, the guide body is configured to have a C-shaped cross section.

  In this case, the outer slide body can be formed into a cylindrical shape that can be easily formed. Accordingly, smooth sliding between the guide body and the outer slide body can be easily realized, and the horizontal displacement of the outer slide body can be effectively prevented.

  Preferably, it is configured to be attached to a septic tank of 10 persons or less.

  As described above, the bubble supply device and the membrane module can be attached and detached easily and accurately even in a small septic tank with a small space during the attachment and detachment work, which is more effective.

  Preferably, the membrane module is configured to include a number of tubular membranes whose upper and lower ends are focused and fixed.

  In this case, since the membrane module is composed of a large number of tubular membranes, the tubular membrane itself has an air lift pump action, and filtration processing is possible even at a position where the liquid level of the liquid to be treated is considerably lowered. Accordingly, it is possible to reduce the size of the submerged membrane separation apparatus by reducing the size of the membrane module, and it is possible to increase the variable capacity of the septic tank, so that the septic tank itself can be further downsized.

  Preferably, the membrane module performs a filtration process by gravity filtration, and is branched into a first pipe opened to the atmosphere and a second pipe leading to a pump for discharging the filtrate at the outlet of the filtrate after the filtration process. A discharge pipe is configured to be connected.

  In this case, when removing the membrane module from the septic tank, the first pipe opened to the atmosphere is connected, so that the liquid level in the membrane module is higher than the liquid level of the liquid to be treated in the septic tank. Therefore, the filtrate in the membrane module flows backward and is naturally discharged to the outside (septic tank).

  Therefore, since the attachment / detachment of the membrane module can be handled in a light weight state without the filtrate, the burden on the operator is reduced, and the attachment / detachment operation can be performed more easily. Moreover, a chemical | medical solution etc. can be poured from a 1st pipe as needed, and a membrane module can be wash | cleaned easily.

  According to the submerged membrane separation apparatus according to the present invention, a special tool is required by installing the bubble supply device and the membrane module while sliding the inner slide body and the outer slide body on the guide body of the septic tank, respectively. The submerged membrane separator can be installed easily and accurately without the need to do so. In addition, even if the attachment and detachment is repeated for maintenance or the like, the attachment can be performed easily and accurately.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partial cross-sectional view of a submerged membrane separation apparatus according to an embodiment of the present invention, as viewed from the side, arranged in a septic tank. FIG. 2 is a partial cross-sectional view of the submerged membrane separation apparatus according to an embodiment of the present invention, as viewed from above, where it is disposed in the septic tank.

  The submerged membrane separation apparatus 1 according to the present invention includes a membrane module 11 that filters a liquid to be treated, a bubble supply device 12 that is attached below the membrane module 11 and supplies bubbles to the membrane module 11, and a bubble supply device 12. An inner slide body 121 that is attached to the side and extends upward, and a pipe-like outer slide body 111 that is attached to the side of the membrane module 11 and in which the inner slide body 121 is slidable in the vertical direction. The outer slide body 111 is configured to be slidable in the vertical direction on the guide body 21 provided in advance in the septic tank 2.

  First, the function of the submerged membrane separation apparatus 1 in the septic tank 2 will be described. The septic tank 2 having a merger processing function is roughly composed of two to three tanks. For example, in the case of 3 tanks, it is comprised from a solid-liquid separation tank, a denitrification tank, and a nitrification tank, and in the case of 2 tanks, it is comprised from a solid-liquid separation tank and a nitrification tank. In the septic tank 2 of this embodiment, as shown in FIG. 2, the tank 22 and the tank 23 are partitioned by a partition plate 24, the tank 22 corresponds to a solid-liquid separation tank or a denitrification tank, and the tank 23 is nitrified. Although it corresponds to a tank, the present invention is not limited to this. The submerged membrane separation apparatus 1 is installed in a nitrification tank 23 and filters domestic wastewater (sewage), which is a liquid to be treated, sent from a preceding tank 22 via a transfer pipe 25 using the activated sludge in the nitrification tank 23. . It should be noted that an alarm (not shown) is configured to be activated when the amount of domestic wastewater transferred suddenly increases or the filtration performance deteriorates and the water level in the nitrification tank 23 exceeds the upper limit HWL.

  In the submerged membrane separation apparatus 1, a bubble supply device 12 is installed below the membrane module 11, and bubbles are fed substantially uniformly into the entire membrane module 11. Bubbles sent from below into the membrane module 11 rise in the membrane module 11 with the liquid to be treated containing activated sludge, and are discharged from the upper end thereof. Thereby, during aeration, the liquid to be treated circulates inside and outside the membrane module 11 in the nitrification tank 23, and during this time, filtration treatment is performed in the membrane module 11.

  The filtrate after the filtration process in the membrane module 11 is discharged through the discharge pipe 13 connected to the filtrate outlet 115. The discharge pipe 13 is branched into a first pipe 14 that is open to the atmosphere and a second pipe 15 that leads to a pump 27 that discharges the filtrate. Thereby, the to-be-processed liquid containing activated sludge is gravity-filtered by making the position of the filtrate exit 115 into the reference | standard of filtration pressure. The filtered filtrate is pumped up by the pump 27 through the second pipe 15 and sent to the disinfection tank 28. The filtrate sent to the sterilization tank 28 is sterilized and discharged from the discharge port 29.

  Next, the attachment / detachment mechanism of the submerged membrane separator 1 will be described in detail. According to the submerged membrane separation device 1 of the present embodiment, the membrane module 11 is installed on the bubble supply device 12. An inner slide body 121 is attached to the side of the bubble supply device 12 via an attachment plate 122. In addition, bands 113 and 114 are attached to the membrane module 11 in the vicinity of the upper end and the lower end of the membrane module 11 so as to surround the periphery, and the outer slide body is attached via an attachment plate 112 attached to the bands 113 and 114. 111 is attached. When these are attached, the work efficiency is improved by replacing them with the actual membrane module 11 after fixing them with an empty container of the same size and accuracy in advance by welding or the like. The bands 113 and 114 are fixed together with a gripping rod 118 for attaching and detaching the membrane module 11 to and from the membrane module 11 by tightening with the bolts and nuts 116. On the other hand, in the septic tank 2, a guide body 21 is fixed in advance to a partition plate 24 with a screw or the like via a stand 26.

  The guide body 21 and the stand 26 are formed of, for example, the same resin material, are integrally fixed by welding or the like, and are attached to the partition plate 24 with a parallelism within about 1 mm per meter, and with the same verticality. It is installed perpendicular to the bottom surface (horizontal plane) of the septic tank 2.

  The outer slide body 111 attached to the membrane module 11 is attached to the guide body 21 so as to be slidable in the vertical direction. In the present embodiment, the outer slide body 111 is cylindrical, and the guide body 21 is configured to have a C-shaped cross section. In this case, the outer slide body 111 can be formed into a cylindrical shape that can be easily formed. Therefore, it is possible to easily realize smooth sliding between the guide body 21 and the outer slide body 111, and it is possible to effectively prevent the horizontal displacement of the outer slide body 111. The open width of the guide body 21 (the width of the groove formed in the vertical direction by the C shape (horizontal length)) is larger than the thickness (horizontal length) of the mounting plates 112 and 122. Yes.

  Further, the inner slide body 121 attached to the bubble supply device 12 is attached so as to be slidable in the vertical direction within the cylindrical pipe of the outer slide body 111. The inner side of the outer slide body 111 is formed in a pipe shape having an opening in the vertical direction, and the inner slide body 121 slides mutually by being formed in a cylindrical shape having a diameter slightly shorter than the diameter of the pipe. It becomes possible. Note that the engagement play between the guide body 21 and the outer slide body 111 is preferably 1 mm or less, and the engagement play between the outer slide body 111 and the inner slide body 121 is also preferably 1 mm or less.

  When installing such a submerged membrane separation apparatus 1 in the septic tank 2, first the inner slide body 121 is positioned by inserting it into the guide body 21 of the septic tank 2, and the bubble supply apparatus 12 is installed by sliding. To do. Subsequently, the membrane module 11 is installed above the bubble supply device 12 by inserting and sliding the outer slide body 111 between the inner slide body 121 and the guide body 21. In this way, the submerged membrane separation apparatus 1 can be installed in the septic tank 2 with an accuracy of 2 mm or less per meter in both horizontal and vertical errors. When the submerged membrane separation apparatus 1 is taken out from the septic tank 2, first, the membrane module 11 is pulled out with the detachable gripping rod 118, and then the bubble supply device 12 is pulled out with the inner slide body 121. It is clear that the mounting accuracy remains almost unchanged even after remounting. Since it is necessary to replace the membrane module 11 at a predetermined cycle, the configuration of the present invention with little change in mounting accuracy is particularly effective. At the time of mounting (remounting), the inner slide body 121 is first inserted and slid into the outer slide body 111 to assemble the submerged membrane separation apparatus 1 outside the septic tank 2 and then the septic tank 2. The outer slide body 111 may be slid on the guide body 21 and installed in the septic tank 2.

  In this way, by installing the bubble supply device 12 and the membrane module 11 while sliding the inner slide body 121 and the outer slide body 111 on the guide body 21 of the septic tank 2, respectively, a special tool is not required. The immersion type membrane separator 1 can be installed easily and accurately. In addition, even if the attachment and detachment is repeated for maintenance or the like, the attachment can be performed easily and accurately.

  In this embodiment, the guide body 21, the outer slide body 111, and the inner slide body 121 are provided in two (two sets). However, the present invention is not limited to this. Good. In the case of a single set, the opening width of the guide body 21 may be slightly larger than the thickness of the mounting plates 112 and 122 in order to make positioning of the submerged membrane separation apparatus 1 effective.

  Here, the configuration of the membrane module 11 of the present embodiment will be described in more detail.

  The membrane module 11 contains a large number of tubular membranes 117 accommodated in a cylindrical container and is focused and fixed by thermosetting resin in the vicinity of both ends (upper and lower ends) (shown by broken lines in FIG. 1). An outlet 115 is provided in the vicinity of the upper end on the side of the membrane module 11. The liquid to be treated containing activated sludge flows inside the tubular membrane 117 as the bubbles supplied from the bubble supply device 12 rise, and is filtered from the inside to the outside. The tubular membrane 117 is manufactured, for example, by the method described in Japanese Patent Publication No. 56-35483. According to this method, the membrane is reinforced with a non-woven fabric to form a composite membrane, and while being spirally wound around a mandrel that defines the inner diameter, ultrasonically welded peripheral portions of each other in the longitudinal direction can be used to obtain an arbitrary inner diameter. Tubular membrane 117 is manufactured continuously. The membrane module 11 used in the septic tank 2 is preferably a tubular membrane 117 having an inner diameter of about 10 mm.

The membrane module 11 has a very light and compact feature. For example, a tubular membrane 117 having an inner diameter of 11 mm and a thickness of 0.2 mm is formed with an inner diameter of about 30 cm so that the effective length is about 50 cm, and the height is about When about 600 tubes are focused and fixed on a 57 cm cylindrical container, the weight of the membrane module 11 is about 7 kg and the effective membrane area is about 10 m ² . it can.

  Further, unlike other types of membrane modules, the tubular membrane 117 itself has an air lift pump action, so that the liquid to be treated containing activated sludge from the filtrate outlet 115 opened to the atmospheric pressure by the first pipe 14. Even if the surface is lowered, the liquid to be treated rises in the tubular membrane 117, so that gravity filtration is continuously performed as long as the liquid to be treated is lifted up to the upper end of the membrane module 11 by this air lift pump action. Thereby, since the variable capacity | capacitance of the nitrification tank 23 can be enlarged, the septic tank 2 itself can also be made compact compared with the case where other types of membrane modules are used.

  Furthermore, when the filtrate outlet 115 is connected to the first pipe 14 opened to the atmosphere, when the membrane module 11 is taken out from the septic tank 2, the liquid level in the membrane module 11 is the liquid level of the liquid to be treated in the septic tank 2. When the height is higher, a reverse pressure is applied to the liquid surface of the liquid to be processed in the membrane module 11, so that the liquid to be processed inside is naturally discharged out of the membrane module 11. For this reason, since the weight of the liquid to be treated is hardly applied and the work can be performed with the weight of the membrane module 11 alone, the number of workers and the labor thereof can be reduced. In particular, in the membrane module 11 as described above, since the weight of the membrane module 11 itself does not exceed 10 kg, the attachment / detachment work can be performed alone. On the other hand, the 1st pipe 14 can also be utilized for the washing | cleaning operation | work of the membrane module 11 by inject | pouring a chemical | medical solution from an air release port as needed.

  The filtrate outlet 115 is connected to a second pipe 15 that guides the filtrate to the pump 27 in addition to the first pipe 14 that is an open pipe. In the present embodiment, the pump 27 is fixed to the septic tank 2 in order to reduce obstacles when the membrane module 11 is attached and detached. For this reason, it is necessary to install the second pipe 15 so that the inconvenience does not occur when the membrane module 11 is taken out from the septic tank 2 and the entire second pipe 15 is not higher than the height of the filtrate outlet 115. . If a part of the second pipe 15 is at a position higher than the filtrate outlet 115, when the liquid surface to be treated is lowered, a part of the second pipe 15 retains air and the filtrate cannot be sent to the pump 27. Because there are cases.

  An air lift pump is used as the pump 27 of the present embodiment. In order to increase the pump efficiency, the inlet of the filtrate is preferably as low as possible. The filtrate that has entered the pump 27 from the second pipe 15 rises along with the air bubbles blown out from the air inlet 261 into the pump 27 and is sent to the disinfection tank 28. It is done. The pump 27 may be fixed to the membrane module 11.

  Next, the configuration of the bubble supply device 12 of this embodiment will be described in more detail.

  The same cylindrical container as the membrane module 11 is used for the bubble supply device 12 of the present embodiment. A positioning tool 123 for correctly mounting the membrane module 11 is provided at the upper end of the container. In addition, a support leg 124 for defining a position (horizontal direction / vertical direction) from the bottom surface of the nitrification tank 23 is attached to the bottom of the container. A bubble generating device 125 is installed in the container, and air sent from an air pump (not shown) is ejected as bubbles from the ejection hole 126 into the liquid to be treated including activated sludge.

  In order to sufficiently exhibit the filtration performance of the membrane module 11 in the submerged membrane separation apparatus 1, it is necessary to uniformly distribute the bubbles over the entire membrane module 11. For example, the bubble supply device 12 is provided with bubble ejection holes 126 having a diameter of about 10 mm at intervals of several centimeters. However, a water depth difference of, for example, 2 mm is generated at the position of the ejection hole 126 (not leveled). In this case, the bubble ejection amount appears as a large difference of about 60%. Accordingly, the bubble supply device 12 is required to have high installation accuracy. Naturally, the membrane module 11 also needs to be installed with high accuracy with respect to the bubble supply device 12.

  Therefore, the septic tank 2 that is a robust structure made of FRP or the like is provided with a guide body 21 that serves as a positioning reference, and the bubble supply device 12 and the membrane module 11 are installed along the guide body 21. The installation accuracy of the bubble supply device 12 and the membrane module 11 with respect to the septic tank 2 and the installation accuracy of the membrane module 11 with respect to the bubble supply device 12 can both be increased, and the filtration performance of the membrane module 11 can be sufficiently exhibited.

  In the container of the bubble supply device 12 according to the present embodiment, a net 127 having a thickness of several mm for removing or subdividing foreign matter and sludge lump that may block the tubular membrane 117 of the membrane module 11 is also attached. ing.

  Sewage such as domestic wastewater treated in the septic tank 2 is various and often clogs the air ejection hole 126 and the net 127. It is necessary that the bubble supply device 12 can be easily pulled out of the septic tank 2 for these inspections and cleaning, and this can be achieved by the configuration of the present invention.

  The configuration of the present invention as described above is an example, and the present invention is not limited thereto. The structure and fixing method of the guide body 21 and the slide bodies 111 and 121 can be changed without departing from the spirit of the present invention. There can be obtained a number of modes having the same effect.

It is the fragmentary sectional view which looked at the place which has arrange | positioned the immersion type membrane separator which concerns on one Embodiment of this invention in the septic tank from the side. It is the fragmentary sectional view which looked at the place which has arrange | positioned the immersion type membrane separator which concerns on one Embodiment of this invention in the septic tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Submerged membrane separator 2 Septic tank 11 Membrane module 12 Bubble supply device 13 Discharge pipe 14 First pipe 15 Second pipe 21 Guide body 27 Pump 111 Outer slide body 115 Filtrate outlet 117 Tubular membrane 121 Inner slide body

Claims (5)

A membrane module for filtering the liquid to be treated;
A bubble supply device that is attached below the membrane module and supplies bubbles to the membrane module;
An inner slide attached to the side of the bubble supply device and extending upward;
A pipe-shaped outer slide body that is attached to the side of the membrane module and in which the inner slide body can slide in the vertical direction,
The outer slide body is configured to be slidable in a vertical direction on a guide body provided in advance in the septic tank.   The immersion type membrane separation apparatus according to claim 1, wherein the guide body has a C-shaped cross section.   The submerged membrane separation apparatus according to claim 1 or 2, wherein the submerged membrane separation apparatus is attached to a septic tank of 10 or fewer tanks.   The submerged membrane separator according to any one of claims 1 to 3, wherein the membrane module includes a number of tubular membranes whose upper and lower ends are fixedly focused.   The membrane module performs a filtration process by gravity filtration, and a discharge pipe branched into a first pipe opened to the atmosphere and a second pipe leading to a pump for discharging the filtrate at the outlet of the filtrate after the filtration process. The submerged membrane separation device according to claim 1, wherein the submerged membrane separation device is connected.

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